xintongsong commented on a change in pull request #9693: [FLINK-13984] Separate on-heap and off-heap managed memory pools URL: https://github.com/apache/flink/pull/9693#discussion_r327957575
########## File path: flink-runtime/src/main/java/org/apache/flink/runtime/memory/MemoryManager.java ########## @@ -394,74 +318,79 @@ public void release(Collection<MemorySegment> segments) { return; } - // -------------------- BEGIN CRITICAL SECTION ------------------- - synchronized (lock) { - if (isShutDown) { - throw new IllegalStateException("Memory manager has been shut down."); - } + Preconditions.checkState(!isShutDown, "Memory manager has been shut down."); - // since concurrent modifications to the collection - // can disturb the release, we need to try potentially multiple times - boolean successfullyReleased = false; - do { - final Iterator<MemorySegment> segmentsIterator = segments.iterator(); + EnumMap<MemoryType, Long> releasedMemory = new EnumMap<>(MemoryType.class); - Object lastOwner = null; - Set<MemorySegment> segsForOwner = null; + // since concurrent modifications to the collection + // can disturb the release, we need to try potentially multiple times + boolean successfullyReleased = false; + do { + Iterator<MemorySegment> segmentsIterator = segments.iterator(); - try { - // go over all segments - while (segmentsIterator.hasNext()) { - - final MemorySegment seg = segmentsIterator.next(); - if (seg == null || seg.isFreed()) { - continue; - } - - final Object owner = seg.getOwner(); - - try { - // get the list of segments by this owner only if it is a different owner than for - // the previous one (or it is the first segment) - if (lastOwner != owner) { - lastOwner = owner; - segsForOwner = this.allocatedSegments.get(owner); - } - - // remove the segment from the list - if (segsForOwner != null) { - segsForOwner.remove(seg); - if (segsForOwner.isEmpty()) { - this.allocatedSegments.remove(owner); - } - } - - if (isPreAllocated) { - memoryPool.returnSegmentToPool(seg); - } - else { - seg.free(); - numNonAllocatedPages++; - } - } - catch (Throwable t) { - throw new RuntimeException( - "Error removing book-keeping reference to allocated memory segment.", t); - } + //noinspection ProhibitedExceptionCaught + try { + MemorySegment segment = null; + while (segment == null && segmentsIterator.hasNext()) { + segment = segmentsIterator.next(); + if (segment.isFreed()) { + segment = null; } + } + while (segment != null) { + segment = releaseSegmentsForOwnerUntilNextOwner(segment, segmentsIterator, releasedMemory); Review comment: I also feel the logic here is quite complicated to understand. I agree that it would be better to keep the current approach to avoid possible regression. For the moment, I suggest we explain the approach and performance concerns in comments for better maintainability. ---------------------------------------------------------------- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. For queries about this service, please contact Infrastructure at: us...@infra.apache.org With regards, Apache Git Services